Anodizing racks



Sept. 12, 1961 K. w. GAULT ANODIZING RACKS Filed Nov. 3, 1958 INVENTOR KENNETH United States Patent O 2,999,802 ANODIZING RACKS Kenneth W. Gault, Newnan, Ga., assignor to The William L. Bonnell Company, Inc., Newnan, Ga. Filed Nov. 3, 1958, Ser. No. 771,657 Claims. (Cl. 204-297) This invention relates to improvements in work holders for use in the electrolytic treatment of metallic articles, and more particularly although not exclusively to an improved anodizing rack for holding aluminum articles or workpieces as they are processed through one or a series of electrolytic baths giving them an anodic finish.

While the desirability of providing a rack capable of firmly holding a plurality of articles to be electrofinished (or electroplated) during their treatment in one or a series of baths while at the same time of permitting simple and speedy racking and unracking of the articles has long been recognized, the prior racks have not proved satisfactory for numerous reasons. Taking by way of example the anodizing racks hitherto used in electrofinishing aluminum articles, such have employed article-holding pins in the form of rods or bars of aluminum possessing little or no resiliency, with the result that they had to be in a sense conformed to the size and configuration of the articles being treated, thus greatly extending racking time, and moreover they had to be pounded back into shape between each use even for articles varying only slightly as to size and/ or shape. Obviously, non-resilient articleholding pins as aforesaid cannot exert any substantial pressure grip on articles held therebetween, with the result that ofttimes articles were lost in the tanks containing the electrolyte. Another serious drawback to the use of anodizing racks employing aluminum pins, as heretofore, is that they must be stripped in caustic after each use of the rack, which is not only time-consuming but also a requirement which greatly reduces the life of the rack, since on the average an aluminum rack lasts only eight times through caustic.

Stated broadly, a principal object of the invention is the provision of an improved article-holding rack for use in holding articles being processed in an electrolytic bath and/ or through a series of baths which may include acids or caustic solution, which rack in contrast to the prior racks serving a similar function, is characterized by the ability to hold the articles to be treated firmly and securely yet with a spring force, thus to avoid the possibility of the articles being marred or otherwise impaired when subjected to the holding action thereof.

Another important object of the invention is the provision of an improved rack of the last stated character whose construction is such as to greatly simplify and speed up article racking and unracking time, as compared to the prior racks serving similar function.

Yet another major object of the invention is the provision of an anodizing rack for holding aluminum shapes or articles being processed through a bath or a series of baths giving them an anodic finish, which is so constructed and constituted that no stripping in caustic after each use is required.

A more particular object of the invention is the provision of an article-holding rack for holding a plurality of articles receiving electrolytic-bath treatment, and which employs upper and lower article-holding pins arranged in pairs and functioning to hold one or more of the articles disposed therebetween, wherein the construction and arrangement of a selected one pin of each pair thereof is such as to render same resiliently deflectable which enables the pin pairs to accommodate and firmly hold the article or articles associated therewith.

Yet another object of the invention is the provision ice of a rack as last stated wherein one pin of each of the article-holding pairs thereof is specially constructed and shaped so as to impart thereto both the necessary deflection and the strength as to firmly yet resiliently secure the article or articles associated therewith, and at the same time to facilitate insertion and removal of the article between and from the pins, without exceeding the stress limit of the material (metal) from which said top pin is fashioned.

Still another object of the invention is the provision of an article-holding anodizing rack of the type incorporating pairs of top and bottom pins, characterized by one pin of each pin pair being of multi-ply resilient construction, by the plies making up said one pin being shaped to have optimum strength for the metal used, and by said metal being one suitable for use in electro-finishing aluminum articles, and more importantly, resistant to the formation thereon of oxides as makes unnecessary the periodic stripping of the rack in caustic.

The above and other objects and advantages of the improved article-holding rack of the present invention will appear from the following detailed description thereof, taken with the accompanying illustrative drawings, wherein- FIG. 1 is a broken-away end elevation of said improved article-holding rack;

FIG. 2 is a section taken along line 22 of FIG. 1, illustrating the triangular configuration of the deflectable article-holding pins of the rack;

FIG. 3 is a perspective view of such a pin illustrating its multi-ply construction; and

FIG. 4 is a diagrammatic view illustrating the preferred manner of blanking out the plurality of laminae or plies which make up a deflectable pin from a sheet of selected metal in strip form.

Referring to the drawings in detail, an article-holding rack generally indicated by reference numeral 10 comprises the basic supporting means for holding a plurality of small articles during the course of a desired electrolytic treatment thereof, and more particularly, but not exclusively, for holding a plurality of aluminum articles such as extruded shapes as they are processed through a series of electrolyte baths giving an anodic finish to said articles. Accordingly the rack 10 comprises an elongated, vertically arranged spine 12 of preferably rectangular section having suitably secured to its upper end a hookshaped member 14 of copper or other suitable conducting material, which is adapted to hook over the usual bus bar arranged above the tank containing the bath, the hook thus serving to suspend the rack above the tank and as a means for electrically connecting it to the bus bar.

The spine 12 mounts a plurality of pairs of vertically spaced, article-holding members 16, 24, hereinafter in the terminology of the art referred to as pins, which extend symmetrically to both sides of the center plane of the spine and which cooperate by holding between their outer ends a plurality of articles to be electrolytically treated, such as the articles indicated in broken lines, FIG. 1.

Illustratively, the upper pin 16 of the pairs thereof is formed in two half lengths or sections 16a, 161), each section being secured at its inner end to a long face of the spine as by bolts 18 extending through vertically elongated openings 20 formed in the right-angularly bent inner end 22 of each pin section. Thus, each top pin section 16a, 16b extends from the spine as a cantilever beam. It will be observed that while top-pin securing means other than that described may be substituted, the particular securing means employed must provide a good electrical connection between the spine 12 and said top PlIlS.

The aforesaid bottom pins 24 preferably take the form of unitary, more or less rigid bars which extend through suitable holes provided therefor in the spine 12. Preferably, said bottom pins are secured to the spine by force-fitting them into said holes, such expedient, in addition to firmly securing the bottom pins to the spine, also providing for an electrical connection between the spine and said bottom pins.

At their free or tip ends, both the top and bottom pins 16, 24 are formed with article-engaging and gripping means. In the case of the top pins 16, such means illustratively comprises an inner, upwardly directed hump 26 and an outer, downwardly directed hump 28, and in the case of the bottom pins 24, such means comprises an upper-face notch 30 and an under-face notch 32. The aforesaid arrangement provides an under-face notch or recess at the outer end of each upper pin and a complemental upper-face notch at the outer end of each bottom pin of a pin pair, and it also provides an under-face notch at the outer end of each bottom pin and a complemental upper-face notch at the outer end of the next lower top pin of the next lower pair of pins, such complemental notches serving to receive opposite edges of the articles to be treated in the manner illustrated in FIG. 1.

FIG. 3 illustrates an important feature of the instant invention according to which the top pin 16 of each of the aforesaid article-holding pin pairs is made of a plurality of superimposed plies or laminae 34 of springy sheet metal, with all such plies having substantially identical configuration and being secured in face engagement by the aforesaid bolts 18 which secure each top pin as a whole to the spine 12. FIG. 3, in conjunction with FIG. 2, further illustrates that the aforesaid plies 34 making up each top pin have the configuration of identical isosceles triangles and that they are secured along their bottom or base sides to the spine 12 so that apices extend outwardly therefrom and together form the tip end of the pin. This shaping of the top-pin plies provides optimum strength for the particular ply metal used and permits each top pin to be computed by the well known cantilever beam formula to obtain the necessary deflection and strength in the pin, without exceeding the elastic limit of the ply metal in any part of the pin.

In contrast to the prior racks employed in imparting an anodic finish to aluminum articles and which require periodic stripping to remove deposited oxides from the exposed ends of the aluminum article-holding pins, the present invention provides that both the top and bottom pins 16, 24 of the pairs thereof be made of titanium, which, as is well known, is a metal on which salts dissolved or otherwise removed from the aluminum articles in the anodic treatment thereof do not deposit. Thus, the bottom pins 24 are made of titanium bar or rod stock of the requisite section as to provide a stable support for the articles to be treated, and the plies 34 making up each of the top pins 16 are fashioned from sheet titanium of the proper gauge. Thus, a rack employing titanium pins according to the invention will have an almost indefinite life, due to the fact that no periodic stripping by treatment with caustic is required, which will be readily distinguishable from the prior article-holding racks serving similar function but which employed aluminum pins, the life of which rarely exceeded eight strippings through caustic. However, it will be understood that, as with the prior racks, the present rack will be coated throughout with a plastisol or equivalent insulating material, except for approximately one inch of the pins at their tip ends, which will be exposed so as to provide current flow to the articles held therebetween.

The number of plies employed in making up the top pins 16 will vary with the amount of pin deflection considered necessary or advisable for the particular articles being treated, which of course depends to a degree on the normal gauge thickness of the titanium sheet stock employed. It is considered that a 6-ply pin made of thin titanium or titanium alloy sheet will be feasible for operations wherein permissible pin deflection is between A"1% under pounds pull varying from 3 to 32, but it will of course be understood that under other conditions the number of plies may be increased to, say, 8 and decreased to 2, and gauge thickness may vary between .015 and .125 (approx). A multi-ply pin as aforesaid may of course be stress-relieved and aged after fabrication.

FIG. 4 is illustrative of a preferred procedure for forming the multiplicity of plies 34 making up the top pins 16 from titanium sheet in strip form, without wastage of metal. According to this procedure, titanium strip of width corresponding to the overall depth dimension of a ply blank is employed, and said ply blanks 34a are stamped from the strip so that one stamping complements the other, with the result that the ply blanks are formed without any wastage whatsoever. Thereupon the ply blanks are suitably worked to provide the angularly bent securing flanges 22 at their inner ends and the reversely directed humps 26, 28 at their free or tip ends. It is of course permissible to assemble and secure together the plies making up each top pin before securing the pin as a whole to the spine 12. In this connection, the elongation of the holes 20 through which the securing bolts 18 pass permits the plies to be superimposed or built up on one another while at the same time providing a horizontal through opening for the securing bolts 18. As generally indicated in FIG. 1, the spacing between the pins of a pair may be varied to effectively rack a range of articles which differ somewhat in size or shape. Of course, racks according to the invention may be custom-built to accommodate a whole line of differently shaped and differently sized articles to be treated, all within the spirit and scope of the present invention.

While the operation of a rack structure as described in the above will, it is believed, be clear from the above description, such as briefly summarized as follows: The articles to be treated may be inserted between the top and bottom pins of the pairs thereof in the manner illustrated connection with the two top pairs of pins in FIG. 1, or if said articles have channel section they may be held by their embracement of a pair of pin ends top and bottom as shown at the lower portion of said view, wherein the dotted-line showings at the end of certain pins indicate articles of various shapes and sizes being treated. The articles will of course be inserted between pins which are spaced apart a distance somewhat less than the corresponding dimension of the article, or greater in the case of articles of channel section as above, with the result that the top pin deflects upon application of the article and thereupon applies a holding force thereto which is sufficient to securely hold the article against the relatively rigid companion bottom pin. consequent to the ability of the pins 16 to deflect, the articles may of course be simply and expeditiously racked andthe same is true as respects unracking of the articles. Also to be noted is that, upon unracking one run of articles having been completed, the rack is reuseable since the top pins 16 return to their original position without any necessity of hammering or otherwise forcing them back in place, and further because no stripping operation to render the racks reuseable after continued use is necessary.

Although throughout the foregoing description the top one of each pin pair has more or less consistently been designated as the one having the deflectable, multi-ply construction of the invention, it is to be understood that such designation was for the purpose of simple disclosure. As a matter of fact, not only may the bottom pins of the pairs, rather than the top pin, have the aforesaid defiectable multi-ply construction, but also for certain rack applications, such will represent preferred or even required construction. Accordingly, it will be clear that il invention is not limited as respects which of the pins of each article-holding pair thereof should have the special multiply construction as herein proposed.

As the above-suggested and other changes could be made in carrying out the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawing shall be interpreted as illustrative and not in a limiting sense.

I claim:

1. A rack for holding articles during their treatment in an electrolyte bath or the like comprising a vertical metallic spine having means on its upper end adapted both to suspend the rack from a bus bar extending over the bath and to conductively engage said bus bar, and a pair of article-holding metallic pins operatively associated with said spine and extending laterally therefrom, said pins being spaced vertically from one another a predetermined distance adapting them to grip an article between their free outer ends, one of said pins comprising a plurality of coextensive plies of springy sheet metal disposed in face engagement and being secured at its inner end to the spine so as to extend therefrom as a cantilever, the portions of the plies together forming the free outer end of said one pin being shaped to provide article-engaging and gripping means.

2. A rack for holding articles during their treatment in an electrolyte bath or the like comprising a vertical metallic spine having means on its upper end adapted both to suspend the rack from a bus bar extending over the bath and to conductively engage said bus bar, and a pair of article-holding metallic pins operatively associated with said spine and extending laterally therefrom, said pins being spaced vertically from one another a predetermined distance adapting them to grip an article between their free outer ends, one of said pins comprising a plurality of coextensive triangular plies of springy sheet metal disposed in face engagement and being secured to one another and to the spine along one corresponding side whereby said one pin extends outwardly from the spine as a cantilever, the apical portions of the plies pposite the secured corresponding sides thereof together forming the article-gripping outer end of said one pin, and the number of the plies making up said one pin being such as to provide a controlled resilient deflection of the outer end of said pin.

3. A rack substantially as set forth in claim 1, wherein said plies and thereby said one pin have isoscelestriangle configuration in plan and said pin is secured along one side thereof to the spine and its apical portion opposite said side provides said article-engaging and gripping means.

4. A rack substantially as set forth in claim 1, wherein the plies making up said one pin have identical triangular configuration and are disposed so that corresponding sides thereof together provide the inner end of the pin and the apices opposite said sides together provide the outer end of the pin.

5. A rack substantially as set forth in claim 1, wherein said plies making up said one pin are fashioned from sheet titanium.

6. A rack substantially as set forth in claim 2, wherein said plies making up said one pin are fashioned from sheet titanium.

7. A rack substantially as set forth in claim 1, wherein said one pin comprises 2 to 8 plies of sheet titanium of gauge ranging from .015 to .125.

8. A pin for an article-holding rack for use in electrotreating processes comprising at least two coextensive plies of resilient sheet titanium having identical triangular shape and being superposed in face engagement, whereby said pin has corresponding triangular shape when viewed in plan, article gripping means disposed at one apex of said pin and a depending flange on the side of said pin opposite said means, said flange including means for securing said pin to a support.

9. A pin for an article-holding rack substantially as set forth in claim 8, wherein said plies are shaped substantially as an isosceles triangle and are secured together along said flanged side.

10. A pin for an article-holding rack substantially as set forth in claim 8, wherein the triangular body portions of the plies are unsecured with respect to one another.

References Cited in the file of this patent UNITED STATES PATENTS 1,010,648 Leffel Dec. 5, 1911 2,891,898 MacLean June 23, 1959 FOREIGN PATENTS 758,430 Great Britain Oct. 3, 1956 OTHER REFERENCES Metal Finishing, December 1954, page 106. Belke: Plating Rack Manual, June 18, 1947, page 48. 

1. A RACK FOR HOLDING ARTICLES DURING THEIR TREATMENT IN AN ELECTROLYTE BATH OR LIKE COMPRISING A VERTICAL METALLIC SPINE HAVING MEANS ON ITS UPPER END ADAPTED BOTH TO SUSPEND THE RACK FROM A BUS BAR EXTENDING OVER THE BATH AND TO CONDUCTIVELY ENGAGE SAID BUS BAR, AND A PAIR OF ARTICLE-HOLDING METALLIC PINS OPERATIVELY ASSOCIATED WITH SAID SPINE AND EXTENDING LATERALLY THEREFROM, SAID PINS BEING SPACED VERTICALLY FROM ONE ANOTHER A PREDETERMINED DISTANCE ADAPTING THEM TO GRIP AN ARTICLE BETWEEN THEIR FREE OUTER ENDS, ONE OF SAID PINS COMPRISING A PLURALITY OF COEXTENSIVE PLIES OF SPRINGY SHEET METAL DISPOSED IN FACE ENGAGEMENT AND BEING SECURED AT ITS INNER END TO THE SPINE SO AS TO EXTEND THEREFROM AS A CANTILEVER, THE PORTIONS OF THE PLIES TOGETHER FORMING THE 